The effect of angiotensin-converting enzyme inhibition on endothelial function and oxidant stress

Immunomodulatory Activity of the Most Commonly Used Antihypertensive Drugs-Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

This review article is focused on antihypertensive drugs, namely angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), and their immunomodulatory properties reported in hypertensive patients as well as in experimental settings involving studies on animal models and cell lines. The immune regulatory action of ACEI and ARB is mainly connected with the inhibition of proinflammatory cytokine secretion, diminished expression of adhesion molecules, and normalization of CRP concentration in the blood plasma. The topic has significant importance in future medical practice in the therapy of patients with comorbidities with underlying chronic inflammatory responses. Thus, this additional effect of immune regulatory action of ACEI and ARB may also benefit the treatment of patients with metabolic syndrome, allergies, or autoimmune disorders.

Enhancement of EPC migration by high-dose lisinopril is superior compared to captopril and ramipril

Background: Angiotensin-converting enzyme (ACE) inhibitors have been shown to promote endothelial progenitor cell (EPC) function. However, the efficacies of different ACE inhibitors in improving the migratory capabilities of ECPs in coronary artery disease (CAD) patients is unclear. This study compared the effectiveness of captopril, lisinopril, and ramipril toward the migration capability of impaired EPCs from CAD patients. Methods: We isolated peripheral blood mononuclear cells (PBMCs), separated EPCs from PBMCs, and divided them into an untreated group (control) and treated groups of captopril, lisinopril, and ramipril at doses of 1mM, 10mM, and 100mM. EPC migration was evaluated using the Boyden chamber assay. Analysis of variance (ANOVA) was performed using SPSS 25.0. Results: This study showed that treatment with captopril, lisinopril, and ramipril starting at the lowest dose (1 mM) increased EPC migration (65,250 ± 6,750 cells; 60,750± 5,030 cells; and 49,500 ± 8,400 cells, respectively) compared to control (43,714 ± 7,216 cells). Increased migration of EPCs was observed by increasing the treatment dose to 10 mM with captopril, lisinopril, and ramipril (90,000 ± 16,837 cells; 79,071 ± 2,043 cells; and 64,285 ± 11,824 cells, respectively). The highest EPC migration was shown for lisinopril 100 mM (150,750 ± 16,380 cells), compared to captopril and ramipril at the same dose (105,750 ± 8112 cells and 86,625 ± 5,845 cells, respectively). Conclusions: Captopril, ramipril, and lisinopril were shown to increase EPC migration in a dose-dependent manner. Low-dose (1 mM) and medium-dose (10 mM) captopril had a larger effect on ECP migration than lisinopril and ramipril. Meanwhile, high-dose lisinopril (100mM) had the highest migration effect, suggesting it may be preferable for promoting EPC migration in CAD patients.

Anthracycline-induced cardiotoxicity and renin-angiotensin-aldosterone system-from molecular mechanisms to therapeutic applications

Few millions of new cancer cases are diagnosed worldwide every year. Due to significant progress in understanding cancer biology and developing new therapies, the mortality rates are decreasing with many of patients that can be completely cured. However, vast majority of them require chemotherapy which comes with high medical costs in terms of adverse events, of which cardiotoxicity is one of the most serious and challenging. Anthracyclines (doxorubicin, epirubicin) are a class of cytotoxic agents used in treatment of breast cancer, sarcomas, or hematological malignancies that are associated with high risk of cardiotoxicity that is observed in even up to 30% of patients and can be diagnosed years after the therapy. The mechanism, in which anthracyclines cause cardiotoxicity are not well known, but it is proposed that dysregulation of renin-angiotensin-aldosterone system (RAAS), one of main humoral regulators of cardiovascular system, may play a significant role. There is increasing evidence that drugs targeting this system can be effective in the prevention and treatment of anthracycline-induced cardiotoxicity what has recently found reflection in the recommendation of some scientific societies. In this review, we comprehensively describe possible mechanisms how anthracyclines affect RAAS and lead to cardiotoxicity. Moreover, we critically review available preclinical and clinical data on use of RAAS inhibitors in the primary and secondary prevention and treatment of cardiac adverse events associated with anthracycline-based chemotherapy.

Preserved endothelial progenitor cell angiogenic activity in African American essential hypertensive patients

Background

African American (AA) subjects with essential hypertension (EH) have greater inflammation and cardiovascular complications than Caucasian EH. An impaired endogenous cellular repair system may exacerbate vascular injury in hypertension, yet whether these differ between AA EH and Caucasian EH remains unknown. Vascular repair by circulating endothelial progenitor cells (EPCs) is controlled by regulators of EPC mobilization, homing, adhesion and new vessel formation, but can be hindered by various cytokines. We hypothesized that EPC levels and function would be impaired in AA EH compared with Caucasian EH, in association with increased levels of inflammatory mediators and EPC regulators.

Methods

CD34+/KDR+ EPCs were isolated from inferior vena cava and renal vein blood samples of AA EH and Caucasian EH patients (n = 18 each) and from peripheral veins of 17 healthy volunteers (HVs) and enumerated using fluorescence-activated cell sorting. Angiogenic function of late-outgrowth endothelial cells expanded from these samples for 3 weeks was tested in vitro. Levels of inflammatory mediators, angiogenic factors and EPC regulators were measured by Luminex.

Results

EPC levels were decreased in both AA and Caucasian EH compared with HVs, whereas their late-outgrowth endothelial cell angiogenic function was comparable. Levels of several inflammatory mediators were elevated in AA EH compared with Caucasian EH and HVs. Contrarily, vascular endothelial growth factor and its receptor-2 were lower. EPC levels inversely correlated with blood pressure in all hypertensive patients and estimated glomerular filtration rate with inflammatory mediators only in AA EH.

Conclusions

Despite lower EPC numbers, decreased vascular endothelial growth factor signaling and inflammation, EPC function is preserved in AA EH compared with Caucasian EH and HVs, suggesting compensatory mechanisms for vascular repair.

Fixed-dose combination of zofenopril plus hydrochlorothiazide vs. irbesartan plus hydrochlorothiazide in hypertensive patients with established metabolic syndrome uncontrolled by previous monotherapy. The ZAMES study (Zofenopril in Advanced MEtabolic Syndrome)

OBJECTIVE

Whether all antihypertensive drugs are equally effective in patients with metabolic syndrome is still unclear. The goal of the Zofenopril in Advanced MEtabolic Syndrome (ZAMES) study was to investigate whether treatment with the fixed-dose combination of sulphydril-containing angiotensin-converting enzyme inhibitor zofenopril plus hydrochlorothiazide is at least as effective as that with the angiotensin receptor blocker irbesartan plus hydrochlorothiazide in patients with metabolic syndrome and essential hypertension, uncontrolled by a previous monotherapy.

METHODS

We enrolled 721 patients in a multicenter, international (Italy and Romania), randomized, double-blind, parallel group, phase III study. Following a 1-week screening withdrawal period, 482 patients (mean age 59 ± 10 years, 53% men) bearing a SBP at least 140 mmHg and/or DBP at least 90 mmHg plus metabolic syndrome (ATP-III criteria) were randomly allocated to a fixed-dose combination of zofenopril 30 mg plus hydrochlorothiazide 12.5 mg or irbesartan 150 mg plus hydrochlorothiazide 12.5 mg once daily for a cumulative period of 24 weeks. After 8 and 16 weeks, zofenopril and irbesartan doses were doubled in nonnormalized study participants. The study endpoint was the office DBP reduction at study end. In 20% of patients, an ambulatory blood pressure monitoring was performed.

RESULTS

The prevalence of diabetes at baseline was significantly (P < 0.05) greater in the zofenopril plus hydrochlorothiazide group (82%) than in the irbesartan plus hydrochlorothiazide (73%) group. Baseline-adjusted DBP reductions were superimposable (P = 0.370) with zofenopril plus hydrochlorothiazide [n = 231; 9.8 (95% confidence interval: 11.1, 8.4) mmHg] and irbesartan plus hydrochlorothiazide [n = 235; 10.4 (11.8, 9.0) mmHg]. The same was for SBP [17.0 (19.2, 14.8) mmHg zofenopril plus hydrochlorothiazide vs. 18.8 (21.0, 16.6) mmHg irbesartan plus hydrochlorothiazide, P = 0.113]. Rate of normalized and responder patients (SBP/DBP < 140/90 mmHg or SBP reduction more than 20 mmHg or DBP reduction more than 10 mmHg) did not differ at study end (65.8% and 77.5% zofenopril plus hydrochlorothiazide vs. 67.7% and 81.5% irbesartan plus hydrochlorothiazide; P = 0.695, P = 0.301). These results were confirmed in the 69 study participants undergoing ambulatory blood pressure monitoring (35 zofenopril plus hydrochlorothiazide; 34 irbesartan plus hydrochlorothiazide), with a comparable 24-h average BP reduction [BP difference between-treatment: SBP: 0.1 (-5.7, 5.9) mmHg, P = 0.975; DBP: -0.9 (-3.8, 2.0) mmHg, P = 0.541]. Both drugs attained similar BP reductions also in the last 6 h of the dosing interval [between-treatment difference SBP: 0.1 (-7.4, 7.5) mmHg P = 0.990; DBP: -0.9 (-4.4, 2.6) mmHg, P = 0.602]. Metabolic and renal indexes were not altered. Few patients were withdrawn for moderate adverse events (5% zofenopril plus hydrochlorothiazide; 5% irbesartan plus hydrochlorothiazide).

CONCLUSION

This is the first study supporting the comparable antihypertensive and metabolic response to fixed-dose combinations of sulphydril-containing angiotensin-converting enzyme inhibitors (zofenopril) or angiotensin receptor blockers (Irbesartan) with a diuretic in patients with advanced metabolic syndrome and nonresponders to monotherapy. The results of this study can further improve the clinical management of high cardiovascular risk patients with hypertension and metabolic syndrome, because these two drug combinations increase the number of available combinations, which may significantly improve patients' adherence in this special clinical condition that is frequently found in everyday practice.

Efficacy of Zofenopril vs. Irbesartan in Combination with a Thiazide Diuretic in Hypertensive Patients with Multiple Risk Factors not Controlled by a Previous Monotherapy: A Review of the Double-Blind, Randomized "Z" Studies

Combinations between an angiotensin converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (ARB) and hydrochlorothiazide (HCTZ) are among the recommended treatments for hypertensive patients uncontrolled by monotherapy. Four randomized, double-blind, parallel group studies with a similar design, including 1469 hypertensive patients uncontrolled by a previous monotherapy and with ≥1 cardiovascular risk factor, compared the efficacy of a combination of a sulfhydryl ACE inhibitor (zofenopril at 30 or 60 mg) or an ARB (irbesartan at 150 or 300 mg) plus HCTZ 12.5 mg. The extent of blood pressure (BP)-lowering was assessed in the office and over 24 h. Pleiotropic features of the treatments were evaluated by studying their effect on systemic inflammation, organ damage, arterial stiffness, and metabolic biochemical parameters. Both treatments similarly reduced office and ambulatory BPs after 18-24 weeks. In the ZODIAC study a larger reduction in high sensitivity C reactive protein (hs-CRP) was observed under zofenopril (-0.52 vs. +0.97 mg/dL under irbesartan, p = 0.001), suggesting a potential protective effect against the development of atherosclerosis. In the ZENITH study the rate of carotid plaque regression was significantly larger under zofenopril (32% vs. 16%; p = 0.047). In the diabetic patients of the ZAMES study, no adverse effects of treatments on blood glucose and lipids as well as an improvement of renal function were observed. In patients with isolated systolic hypertension of the ZEUS study, a slight and similar improvement in renal function and small reductions in pulse wave velocity (PWV), augmentation index (AI), and central systolic BP were documented with both treatments. Thus, the fixed combination of zofenopril and HCTZ may have a relevant place in the treatment of high-risk or monotherapy-treated uncontrolled hypertensive patients requiring a more prompt, intensive, and sustained BP reduction, in line with the recommendations of current guidelines.

Evaluation of the role of captopril on clozapine-induced cardiotoxicity and hematotoxicity in adult male albino rats

Clozapine (CLZ) is considered the most effective drug in treatment of resistant schizophrenia. However, its cardiotoxic effect has raised concerns about its safety. Captopril is a well-known angiotensin-converting enzyme inhibitor with unique antioxidant properties. The aim of this study was to investigate the protective effect of captopril against CLZ-induced myocarditis, and since both drugs have hematotoxic effects, this study aimed to clarify the effect of their combined use on the bone marrow. The study was conducted for 4 weeks on 50 adult male albino rats divided into five groups: group I (negative control), group II (positive control), group III treated with captopril 5 mg/kg/day, group IV treated with CLZ 25 mg/kg/day, and group V treated with captopril (5 mg/kg) 1 hour before CLZ (25 mg/kg/day). CLZ group showed a significant increase in serum troponin I, marked histopathological changes, and immunohistochemical staining of DNA degradation product 8-hydroxy-2-deoxy guanosine (8-OHdG). It significantly increased malondialdehyde level and decreased glutathione peroxidase. Captopril coadministration decreased the histopathological hallmarks and biochemical marker of myocarditis and attenuated CLZ effects on the oxidative stress parameters and 8-OHdG, suggesting its protective action against CLZ-induced myocarditis. Complete blood count and bone marrow evaluation was normal indicating that captopril, in the protective dose given, didn’t increase the risk of CLZ-induced hematotoxicity

Collateral Growth in the Peripheral Circulation: A Review

Arterial occlusive diseases are a major cause of morbidity and death in the United States. The enlargement of pre-existing vessels, which bypass the site of arterial occlusion, provide a natural way for the body to compensate for such obstructions. Individuals differ in their capacity to develop collateral vessels. In recent years much attention has been focused upon therapy to promote collateral development, primarily using individual growth factors. Such studies have had mixed results. Persistent controversies exist regarding the initiating stimuli, the processes involved in enlargement, the specific vessels that should be targeted, and the most appropriate terminology. Consequently, it is now recognized that more research is needed to extend our knowledge of the complex process of collateral growth. This basic science review addresses five questions essential in understanding current problems in collateral growth research and the development of therapeutic interventions.

Antioxidant and Cardioprotective Properties of the Sulphydryl Angiotensinconverting Enzyme Inhibitor Zofenopril

Zofenopril, a new potent sulphydryl angiotensin-converting enzyme (ACE) inhibitor, is characterized by high lipophilicity, selective cardiac ACE inhibition, and antioxidant and tissue protective activities. In vitro and in vivo experiments suggest that zofenopril exerts antioxidant properties at clinically achievable tissue concentrations. In endothelial cells, zofenopril enhances nitric oxide production, attenuates atherosclerotic lesion development and inhibits adhesion molecule expression by reducing reactive oxygen species. These peculiar characteristics are reflected in the drug's cardioprotective activity, which has been shown to be greater than that of non-sulphydryl ACE inhibitors. Cardiac hypertrophy was also reduced by chronic zofenopril administration, independently of its blood pressure-reducing effect. ACE inhibitors with a sulphydryl group could have an advantage in improving vascular function and reducing cardiac impairment compared with non-sulphydryl-containing ACE inhibitors. This could explain zofenopril's remarkable clinical efficacy post-infarction, and potentially beneficial use in prevention and therapy of cardiovascular diseases, such as atherosclerosis, thrombosis and heart failure.

Targeting endothelial cell metabolism for cardio-protection from the toxicity of antitumor agents

The vascular endothelium plays a fundamental role in the maintenance of tissue homeostasis, regulating local blood flow and other physiological processes. Chemotherapeutic drugs and target therapies, including antiangiogenic drugs targeting vascular endothelial growth factor (VEGF) or its receptors, not only efficiently act against tumor growth, but may also induce endothelial dysfunction and cardiovascular toxicity. Continued research efforts aim to better understand, prevent and mitigate these chemotherapy associated cardiovascular diseases. Conventional chemotherapeutic agents, such as anthracyclines, platinum compounds, and taxanes, and newer targeted agents, such as bevacizumab, trastuzumab, and tyrosine kinase inhibitors, have known risk of cardiovascular toxicity, which can limit their effectiveness by promoting increased morbidity and/or mortality. This review describes a) the activity of anticancer agents in inducing endothelial dysfunction, b) the metabolic pathways and signalling cascades which may be targeted by protective agents able to maintain or restore endothelial cell function, such as endothelial nitric oxide synthase/fibroblast growth factor-2 (eNOS-FGF-2) pathway, and c) the drugs/strategies reported to improve endothelial function and to reduce the risks of cardiovascular diseases such as angiotensin converting enzyme inhibitors (ACEi) and beta blockers, that are fundamental therapies in chronic heart failure (HF), as well as non-standard HF treatments such ad nitric oxide donors and antioxidant strategies. There is increasing interest in whether ACEi, beta-blockers, and/or statins might prevent and/or therapeutically control cardiotoxic effects in cancer patients. Maintaining endothelial function during or following treatments with chemotherapeutic agents, without affecting anti-tumor drug-effectiveness, is essential for preserving or recovering cardiovascular homeostasis. In this respect, the early detection and immediate therapy of cardiovascular toxicity appear crucial for substantial recovery of cardiac function in cancer patients.

Captopril Pretreatment Produces an Additive Cardioprotection to Isoflurane Preconditioning in Attenuating Myocardial Ischemia Reperfusion Injury in Rabbits and in Humans

Background. Pretreatment with the angiotensin-converting inhibitor captopril or volatile anesthetic isoflurane has, respectively, been shown to attenuate myocardial ischemia reperfusion (MI/R) injury in rodents and in patients. It is unknown whether or not captopril pretreatment and isoflurane preconditioning (Iso) may additively or synergistically attenuate MI/R injury. Methods and Results. Patients selected for heart valve replacement surgery were randomly assigned to five groups: untreated control (Control), captopril pretreatment for 3 days (Cap3d), or single dose captopril (Cap1hr, 1 hour) before surgery with or without Iso (Cap3d+Iso and Cap1hr+Iso). Rabbit MI/R model was induced by occluding coronary artery for 30 min followed by 2-hour reperfusion. Rabbits were randomized to receive sham operation (Sham), MI/R (I/R), captopril (Cap, 24 hours before MI/R), Iso, or the combination of captopril and Iso (Iso+Cap). In patients, Cap3d+Iso but not Cap1hr+Iso additively reduced postischemic myocardial injury and attenuated postischemic myocardial inflammation. In rabbits, Cap or Iso significantly reduced postischemic myocardial infarction. Iso+Cap additively reduced cellular injury that was associated with improved postischemic myocardial functional recovery and reduced myocardial apoptosis and attenuated oxidative stress. Conclusion. A joint use of 3-day captopril treatment and isoflurane preconditioning additively attenuated MI/R by reducing oxidative stress and inflammation.

Endothelial progenitor cells in cardiovascular diseases

Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells (EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vasculogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk factors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardiovascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evaluate the challenges facing EPC research and how these may be overcome.

Microscopic modeling of País grape seed extract absorption in the small intestine

The concentration profiles and the absorbed fraction (F) of the País grape seed extract in the human small intestine were obtained using a microscopic model simulation that accounts for the extracts' dissolution and absorption. To apply this model, the physical and chemical parameters of the grape seed extract solubility (C s), density (ρ), global mass transfer coefficient between the intestinal and blood content (k) (effective permeability), and diffusion coefficient (D) were experimentally evaluated. The diffusion coefficient (D = 3.45 × 10(-6) ± 5 × 10(-8) cm(2)/s) was approximately on the same order of magnitude as the coefficients of the relevant constituents. These results were chemically validated to discover that only the compounds with low molecular weights diffused across the membrane (mainly the (+)-catechin and (-)-epicatechin compounds). The model demonstrated that for the País grape seed extract, the dissolution process would proceed at a faster rate than the convective process. In addition, the absorbed fraction was elevated (F = 85.3%). The global mass transfer coefficient (k = 1.53 × 10(-4) ± 5 × 10(-6) cm/s) was a critical parameter in the absorption process, and minor changes drastically modified the prediction of the extract absorption. The simulation and experimental results show that the grape seed extract possesses the qualities of a potential phytodrug.

The sulphydryl containing ACE inhibitor Zofenoprilat protects coronary endothelium from Doxorubicin-induced apoptosis

Pediatric and adult cancer patients, following the use of the antitumor drug Doxorubicin develop cardiotoxicity. Pharmacological protection of microvascular endothelium might produce a double benefit: (i) reduction of myocardial toxicity (the primary target of Doxorubicin action) and (ii) maintenance of the vascular functionality for the adequate delivery of chemotherapeutics to tumor cells. This study was aimed to evaluate the mechanisms responsible of the protective effects of the angiotensin converting enzyme inhibitor (ACEI) Zofenoprilat against the toxic effects exerted by Doxorubicin on coronary microvascular endothelium. We found that exposure of endothelial cells to Doxorubicin (0.1-1μM range) impaired cell survival by promoting their apoptosis. ERK1/2 related p53 activation, but not reactive oxygen species, was responsible for Doxorubicin induced caspase-3 cleavage. P53 mediated-apoptosis and impairment of survival were reverted by treatment with Zofenoprilat. The previously described PI-3K/eNOS/endogenous fibroblast growth factor signaling was not involved in the protective effect, which, instead, could be ascribed to cystathionine gamma lyase dependent availability of H2S from Zofenoprilat. Furthermore, considering the tumor environment, the treatment of endothelial/tumor co-cultures with Zofenoprilat did not affect the antitumor efficacy of Doxorubicin. In conclusion the ACEI Zofenoprilat exerts a protective effect on Doxorubicin induced endothelial damage, without affecting its antitumor efficacy. Thus, sulfhydryl containing ACEI may be a useful therapy for Doxorubicin-induced cardiotoxicity.

MRI biomarkers for evaluation of treatment efficacy in preclinical diabetic retinopathy

INTRODUCTION

One sober consequence of the current epidemic of diabetes mellitus is that an increasing number of people world-wide will partially or completely lose their sight to diabetic retinopathy. Clinically, the sight-threatening complications of diabetes are diagnosed and treated based on visible retinal lesions (e.g., dot-blot hemorrhages or retinal neovascularization). However, such anatomical microvascular lesions are slow to respond with treatment. Thus, there remains an urgent need for imaging biomarkers that are abnormal before retinal lesions are visibly apparent and are responsive to treatment.

AREAS COVERED

Here, the development of new MRI methods, such as manganese-enhanced MRI, for evaluating early diabetes-evoked retinal pathophysiology, and its usefulness in guiding new treatments for diabetic retinopathy are reviewed.

EXPERT OPINION

In diabetic retinopathy, not all important diagnostic and prognostic needs are well served by optical methods. In the absence of gross anatomy changes, critical times when drug intervention is most likely to be successful at reducing vision loss are missed by most light-based methods and thus provide little help in guiding diagnosis and treatment. For example, before clinical symptoms, is there an optimal time to intervene with drug therapy? Is a drug reaching its target? How does one assess optimal drug dose, schedule, and routes? How well do current experimental models mimic the clinical condition? As discussed herein, MRI is as an analytical tool for addressing these unmet needs. Future clinical applications of MRI can be envisioned such as in clinical trials to assess drug treatment efficacy, or as an adjunct approach to refine or clarify a difficult clinical case. New MRI-generated hypotheses about the pathogenesis of diabetic retinopathy and its treatment are discussed. In the coming years, a substantial growth in the development and application of MRI is expected to address relevant question in both the basic sciences and in the clinic.

Carotid artery intima-media thickness and the renin-angiotensin system

Carotid artery intima-media thickness (IMT) is a biomarker for cardiovascular disease that also predicts the risk of cardiovascular mortality. Angiotensin-converting enzyme (ACE) inhibition is a unique therapeutic modality because it both treats hypertension and improves arterial health and cardiovascular disease outcomes. Controversy exists regarding the role of ACE inhibitors and angiotensin receptor blockers (ARBs) in IMT regression. Our article provides an update on how ACE inhibitors and ARBs could play a role in decreasing IMT.

POTENTIAL OF THE MODERN ACE INHIBITOR ZOFENOPRIL IN CLINICAL PRACTICE: CARDIOPROTECTIVE, ANTI-ISCHEMIC, AND ANTIATHEROGENIC EFFECTS

The review discusses various aspects of angiotensin-converting enzyme (ACE) inhibitor therapy in patients with cardiovascular disease (CVD), including acute myocardial infarction (AMI). The focus is on the modern ACE inhibitor zofenopril, its specific pharmacological characteristics, and additional cardioprotective, anti-ischemic, and antiatherogenic effects. The existing evidence of clinical effectiveness of zofenopril and its potential for a wider use in clinical practice are also addressed. 

Antioxidant effect of captopril and enalapril on reactive oxygen species-induced endothelial dysfunction in the rabbit abdominal aorta

BACKGROUND

Reactive oxygen species (ROS) are known to be related to cardiovascular diseases. Many studies have demonstrated that angiotensin-converting enzyme inhibitors have beneficial effects against ROS. We investigated the antioxidant effect of captopril and enalapril in nitric oxide mediated vascular endothelium-dependent relaxations.

MATERIALS AND METHODS

Isolated rabbit abdominal aorta ring segments were exposed to ROS by electrolysis of the organ bath medium (Krebs-Henseleit solution) after pretreatment with various concentrations (range, 10(-5) to 3×10(-4) M) of captopril and enalapril. Before and after electrolysis, the endothelial function was measured by preconstricting the vessels with norepinephrine (10(-6) M) followed by the cumulative addition of acetylcholine (range, 3×10(-8) to 10(-6) M). The relevance of the superoxide anion and hydrogen peroxide scavenging effect of captopril and enalapril was investigated using additional pretreatments of diethyldithiocarbamate (DETCA, 0.5 mM), an inhibitor of Cu/Zn superoxide dismutase, and 3-amino-1,2,4-triazole (3AT, 50 mM), an inhibitor of catalase.

RESULTS

Both captopril and enalapril preserved vascular endothelium-dependent relaxation after exposure to ROS in a dose-dependent manner (p<0.0001). Pretreatment with DETCA attenuated the antioxidant effect of captopril and enalapril (p<0.0001), but pretreatment with 3AT did not have an effect.

CONCLUSION

Both captopril and enalapril protect endothelium against ROS in a dose-dependent fashion in isolated rabbit abdominal aortas. This protective effect is related to superoxide anion scavenging.

Protective effects of captopril in diabetic rats exposed to ischemia/reperfusion renal injury

Objectives

To investigate the potential protective effects of captopril, the angiotensin-converting enzyme inhibitor, in diabetic rats exposed to ischaemia/reperfusion (I/R) renal injury.

Methods

Following successful induction of diabetes, captopril treatment (50 mg/kg/day, p.o.) was applied for 4 weeks, after which bilateral renal ischaemia was induced for 30 min followed by reperfusion for 24 h.

Results

Captopril significantly attenuated hyperglycaemia and hypoinsulinaemia in diabetic rats, and significantly reduced the elevations of serum creatinine and aldosterone levels, and renal malondialdehyde, tumour necrosis factor-α and nitric oxide (NO), and prevented the depletion of reduced glutathione caused by I/R in diabetic rats. Histopathological renal tissue damage induced by I/R in diabetic rats was ameliorated by captopril treatment. Immunohistochemical analysis revealed that captopril significantly attenuated the reduction of insulin content in pancreatic islet β-cells, and decreased the I/R-induced expression of inducible NO synthase, nuclear factor-κB, Fas ligand and caspase-3, and increased the expression of survivin and heme oxygenase-1 in the kidney tissue of diabetic rats.

Conclusions

Captopril represents a potential candidate to reduce the risk of renal injury induced by ischaemia/reperfusion in type 2 diabetes.

Long-term treatment with sulfhydryl angiotensin-converting enzyme inhibition reduces carotid intima-media thickening and improves the nitric oxide/oxidative stress pathways in newly diagnosed patients with mild to moderate primary hypertension

Aim. Sulfhydryl angiotensin-converting enzyme (ACE) inhibitors exert antiatherosclerotic effects in preclinical models and antioxidant effects in patients. However, whether ACE inhibitors have any clinically significant antiatherogenic effects remains still debated. Objectives. In mildly hypertensive patients, we evaluated the effect of the sulfhydryl ACE inhibitor zofenopril in comparison with the carboxylic ACE inhibitor enalapril on carotid atherosclerosis (intima-media thickness [IMT] and vascular lumen diameter) and systemic oxidative stress (nitrite/nitrate, asymmetrical dimethyl-L-arginine, and isoprostanes). Material and methods. In 2001, we started a small prospective randomized clinical trial on 48 newly diagnosed mildly hypertensive patients with no additional risk factors for atherosclerosis (eg, hyperlipidemia, smoke habit, familiar history of atherosclerosisrelated diseases or diabetes). Patients were randomly assigned either to the enalapril (20 mg/d, n = 24) or the zofenopril group (30 mg/d, n = 24); the planned duration of the trial was 5 years. Carotid IMT and vascular lumen diameter were determined by ultrasonography for all patients at baseline and at 1, 3, and 5 years. Furthermore, nitrite/nitrate, asymmetrical dimethyl-L-arginine, and isoprostane levels were measured. Results. In our conditions, IMT of the right and left common carotid arteries was similar at baseline in both groups (P = NS). Intima-media thickness measurements until 5 years revealed a significant reduction in the zofenopril group but not in the enalapril group (P b .05 vs enalapril-treated group). This effect was coupled with a favorable nitric oxide/oxidative stress profile in the zofenopril group. Conclusion. Long-term treatment with the sulfhydryl ACE inhibitor zofenopril besides its blood pressure–lowering effects may slow the progression of IMT of the carotid artery in newly diagnosed mildly hypertensive patients. (Am Heart J 2008;156:1154.e1-1154.e8.)

The anti-oxidant and anti-apoptotic effects of nebivolol and zofenopril in a model of cerebral ischemia/reperfusion in rats

The aim of this experiment was to investigate whether nebivolol and zofenopril have protective effects against oxidative damage and apoptosis induced by cerebral ischemia/reperfusion (I/R). There were seven groups of rats, with each containing eight rats. The groups were: the control group, I/R group, I/R plus zofenopril, I/R plus nebivolol, I/R plus nebivolol and zofenopril, zofenopril only and nebivolol only. Cerebral I/R was induced by clamping the bilateral common carotid artery and through hypotension. The rats were sacrificed 1h after ischemia, and histopathological and biochemical analyses were carried out on their brains. The total antioxidant capacity was evaluated by using an automated and colorimetric measurement method developed by Erel. I/R produced a significant increase in the levels of total oxidant status and malondialdehyde levels, the number of caspase-3 immunopositive cells and activities of prolidase and paraoxonase in brain when compared with the control group (p<0.05). A significant decrease in brain total antioxidant capacity and nitric oxide levels were found in I/R group when compared with the control group (p<0.05). Both nebivolol and zofenopril treatment prevented decreasing of the total antioxidant capacity and nitric oxide levels, produced by I/R in the brain (p<0.05). Both nebivolol and zofenopril treatment prevented the total oxidant status, malondialdehyde levels, activities of paraoxonase and prolidase from increasing in brains of rats exposed to I/R (p<0.05). In conclusion, both nebivolol and zofenopril protected rats from ischemia-induced brain injury. The protection may be due to the indirect prevention of oxidative stress and apoptosis.

Safety and efficacy of the sulfydryl ACE-inhibitor zofenopril in the management of cardiovascular disease

In the 1970s, pharmacological therapy interrupting the renin-angiotensin system was considered beneficial for patients with high-renin hypertension. Angiotensin-converting enzyme (ACE) inhibitors proved to be effective not only in patients with high renin and elevated blood pressure, but also in many hypertensive patients with normal levels of plasma renin activity. ACE inhibitors are used in a wide range of chronic illnesses such as atherosclerosis, hypertension, myocardial infarction, heart failure, diabetic complications, and stroke. To date, more than ninety controlled clinical trials evaluating the beneficial effects of 14 different ACE inhibitors were conducted. Moreover, data from experimental studies showed that ACE inhibitors can attenuate the development of atherosclerosis, oxidative stress, and vascular inflammation in a wide range of species indicating that ACE inhibition also favourably affects the vasculature. More than fifteen years ago, the bi-sulfydryl ACE-inhibitor zofenopril has shown an excellent clinical safety and efficacy in patients with hypertension and in those with myocardial infarction. More recently, this compound exhibited a potent antioxidant and antiatherosclerotic effect indicating a clinical useful vasoprotective action.

Zofenopril in the treatment of patients with arterial hypertension and stable coronary heart disease: effects on oxidative stress and flowdependent vasodilatation

Aim. To compare the effects of ACE inhibitors zofenopril and perindopril on endothelial function and oxidative stress (OS) in patients with stable CHD and AH. Material and methods. In total, 40 patients with stable CHD (Functional Class II-III effort angina) and Stage 1-2 AH received zofenopril (7,5-30 mg/d; mean dose 18,6±8,8 mg/d; n=17) or perindopril (2-8 mg/d; mean dose 4,1±2,1 mg/d; n=23) for 12 weeks. At baseline and in the end of the study, all patients underwent reactive hyperemia test (RHT), to assess flow-dependent vasodilatation of brachial artery, and the measurement of OS parameters (malone dialdehyde, MDA, in low-density lipoproteins, MDALDL) and antioxidant parameters (superoxide dismutase (SOD) and glutathione peroxidase (GPO) activity in erythrocytes).

Results. In both groups, a similar reduction in systolic and diastolic blood pressure levels was observed. In the zofenopril group, a significant elevation in brachial artery diameter increase during RHT, a significant increase in GPO activity, and some reduction in MDALDL levels were observed, which points to antioxidant system (AOS) activation and OS reduction. No similar changes of these parameters were observed in the perindopril group. Conclusion. In patients with stable CHD and AH, zofenopril, but not perindopril, reduced OS severity and increased AOS system activity, which was associated with improved endothelial-dependent vasodilatation.

Effects of ACE inhibition on circulating endothelial progenitor cells, vascular damage, and oxidative stress in hypertensive patients

PURPOSE

The pathogenic role of angiotensin-converting enzyme (ACE) inhibition in hypertensive patients regarding endothelial progenitor-cell (EPC) function is still poorly understood. The aim of the study was to evaluate EPC number, function, and relationship to carotid intima media thickness (IMT) progression.

METHODS

We studied 36 newly diagnosed mildly hypertensive patients free of cardiovascular disease and related risk factors without prior or concurrent therapy with ACE inhibitors. Patients were randomized to receive enalapril 20 mg/day (n = 18) or zofenopril 30 mg/day (n = 18). EPC number and migrating capacity, plasma nitrite and nitrate (NOx), and isoprostane concentrations were evaluated. Carotid IMT was determined by ultrasonography at baseline and after 1 and 5 years of follow-up.

RESULTS

EPC number increased during the follow-up, with no statistical differences between treatment groups. There was an inverse correlation between circulating EPCs and IMT increase over time. Plasma NOx decreased during the study without evident differences between treatment groups. Isoprostanes decreased more markedly in zofenopril-treated patients. Multiple linear regression model demonstrated that carotid IMT was significantly inversely correlated with EPC but not with migratory cells after adjusting for confounders.

CONCLUSIONS

The study demonstrated that EPC levels increased during the follow-up in both groups of newly diagnosed hypertensive patients treated with ACE inhibitors. These drugs prevented progression of vascular damage, with an inverse correlation between circulating EPC levels and IMT values.

Central Pressure and Biomarker Responses to Renin Inhibition with Hydrochlorothiazide and Ramipril in Obese Hypertensives: The ATTAIN Study

BACKGROUND/AIMS

In obese, hypertensive subjects, the renin-angiotensin system (RAS) is enhanced and natriuresis impaired, suggesting a role for combination RAS blockade with diuretics. Data suggest that renin inhibition may attenuate diuretic-induced RAS activation and oxidative stress.

METHODS

In this 8-week, double-blind study of 386 obese individuals (mean body mass index: 35.3) with stage 2 hypertension (mean age: 54.9 years; mean sitting systolic blood pressure, SBP: ≧160 but <200 mm Hg), we compared the efficacy of aliskiren + hydrochlorothiazide (HCTZ) in reducing blood pressure (BP), plasma renin activity (PRA), and a urinary marker of oxidative stress to ramipril. Subjects were randomized to aliskiren/HCTZ 150/12.5 mg or ramipril 5 mg for 1 week, and after the 1st week force titrated to aliskiren/HCTZ 300/25 mg or ramipril 10 mg for 7 weeks.

RESULTS

After 8 weeks, aliskiren/HCTZ provided greater reductions in office BP than ramipril (-28.1/-10.1 vs. -16.6/-3.6 mm Hg, p < 0.0001) as well as 24-hour ambulatory and central pressure measures. Aliskiren/HCTZ also lowered PRA (-45 vs. +83%) and the urinary F2-isoprostane/creatinine ratio (-18 vs. +7%) to a greater extent than ramipril. Adverse events (AEs) were similar in the two groups (35.8% with aliskiren/HCTZ vs. 37.3% on ramipril reporting at least one AE).

CONCLUSIONS

Our findings suggest that the aliskiren/HCTZ combination reduced BP, PRA, and isoprostanes to a greater extent than did ramipril in obese patients with stage 2 hypertension.

No altered blood pressure and serum markers of oxidative stress after a long time dietary fish oil in the genetically 9 month-old type-2 diabetes Zucker rat

In this study, we investigated the effect of a high n-3 fatty acid diet (eicosapentaenoic and docosahexaenoic acids) in Zucker obese and lean rats on blood pressure in association with physiological parameters, serum biochemistry and oxidative stress analysis. After 150 days of treatment, dietary fish oil supplementation in Zucker obese rats (9 months of age) reduces bodyweight gain and serum triglyceridemia and nitrite levels, increases serum glucose and angiotensin converting enzyme activity, but does not alter blood pressure, cholesterol levels and serum markers of oxidative stress (malondialdehyde, glutathione), compared to the Zucker rats fed control diet. According to these results, we can consider that after 150 days of treatment, fish oil is not enough to regulate parameters involved in the metabolic syndrome, such as cholesterolemia and blood pressure, in a 9 month-old genetically type-2 diabetes rat.

Effect of daily fruit ingestion on angiotensin converting enzyme activity, blood pressure, and oxidative stress in chronic smokers

OBJECTIVE

This study examined whether, daily fruit (blueberries) consumption (250 g) for three weeks or acute fruit ingestion (250 g) would attenuate angiotensin converting enzyme (ACE) activity and reduce oxidative stress in chronic cigarette smokers.

METHODS

Twenty subjects were recruited and randomized into fruit or control groups. Blood samples and blood pressure were obtained at baseline and then pre and one hour post when subjects returned to the lab three weeks later. To examine acute effects, the fruit group immediately ingested 250 g of blueberries after returning and at least one hour prior to the post blood draw. Plasma samples were analyzed for ACE activity, F(2)- isoprostanes and lipid hydroperoxides (LH) as measures of oxidative stress, and ferric reducing ability of plasma (FRAP) as a measure of antioxidant potential. A 2 (treatment) x 3 (time) repeated measures ANOVA was used for statistical analysis. If interaction was significant, then Student's t-tests were used to further examine this relationship. For these comparisons, a Bonferroni adjustment was made with statistical significance set at P < 0.025.

RESULTS

The pattern of change between treatments was not significant for any variable except LH (P < 0.001).

CONCLUSION

This study indicates that LH are significantly reduced by daily fruit consumption, but not affected by acute ingestion. This finding could be one way in which fruit consumption contributes to prevention of cardiovascular disease.

Different effects of angiotensin converting enzyme inhibitors on endothelin-1 and nitric oxide balance in human vascular endothelial cells: evidence of an oxidant-sensitive pathway

Angiotensin converting enzyme inhibitors (ACE-I) are able to reduce the formation of the potent vasoconstrictor endothelin-1 and increase nitric oxide bioavailability in human vascular endothelial cells (HUVECs). We tested the effects of two sulfhydryl-containing ACE-I, zofenoprilat, and captopril, and two nonsulfhydryl containing ACE-I, enalaprilat and lisinopril, on endothelin-1/nitric oxide balance and oxidative stress in HUVECs. All the four tested ACE-I reduced endothelin-1 secretion and increased nitric oxide metabolite production by HUVECs. However, zofenoprilat (−42% after 8 hours of incubation) was more effective (P < .05) than enalaprilat (−25%), lisinopril (−21%), and captopril (−30%) in reducing endothelin-1 secretion. Similarly, zofenoprilat (+110% after 8 hours of incubation) was more effective (P < .05) than enalaprilat (+64%), lisinopril (+63%), and captopril (+65%) in increasing nitric oxide metabolite production. The effect of ACE-I on endothelin-1 and nitric oxide metabolite production is mediated by the activation of bradykinin B₂ receptor being counteracted, at least in part, by a specific antagonist. Zofenoprilat and, to a lesser extent, captopril also reduced oxidative stress in HUVECs. In conclusion, among the four tested ACE-I, zofenoprilat was more effective in improving endothelin-1/nitric oxide balance in HUVECs likely because of its greater antioxidant properties.

Long-term treatment with sulfhydryl angiotensin-converting enzyme inhibition reduces carotid intima-media thickening and improves the nitric oxide/oxidative stress pathways in newly diagnosed patients with mild to moderate primary hypertension

BACKGROUND

Sulfhydryl angiotensin-converting enzyme (ACE) inhibitors exert antiatherosclerotic effects in preclinical models and antioxidant effects in patients. However, whether ACE inhibitors have any clinically significant antiatherogenic effects remains still debated.

OBJECTIVES

In mildly hypertensive patients, we evaluated the effect of the sulfhydryl ACE inhibitor zofenopril in comparison with the carboxylic ACE inhibitor enalapril on carotid atherosclerosis (intima-media thickness [IMT] and vascular lumen diameter) and systemic oxidative stress (nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostanes).

METHODS

In 2001, we started a small prospective randomized clinical trial on 48 newly diagnosed mildly hypertensive patients with no additional risk factors for atherosclerosis (eg, hyperlipidemia, smoke habit, familiar history of atherosclerosis-related diseases or diabetes). Patients were randomly assigned either to the enalapril (20 mg/d, n = 24) or the zofenopril group (30 mg/d, n = 24); the planned duration of the trial was 5 years. Carotid IMT and vascular lumen diameter were determined by ultrasonography for all patients at baseline and at 1, 3, and 5 years. Furthermore, nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostane levels were measured.

RESULTS

In our conditions, IMT of the right and left common carotid arteries was similar at baseline in both groups (P = NS). Intima-media thickness measurements until 5 years revealed a significant reduction in the zofenopril group but not in the enalapril group (P < .05 vs enalapril-treated group). This effect was coupled with a favorable nitric oxide/oxidative stress profile in the zofenopril group.

CONCLUSIONS

Long-term treatment with the sulfhydryl ACE inhibitor zofenopril besides its blood pressure-lowering effects may slow the progression of IMT of the carotid artery in newly diagnosed mildly hypertensive patients.

Lack of association of colonic epithelium telomere length and oxidative DNA damage in Type 2 diabetes under good metabolic control

BACKGROUND

Telomeres are DNA repeat sequences necessary for DNA replication which shorten at cell division at a rate directly related to levels of oxidative stress. Critical telomere shortening predisposes to cell senescence and to epithelial malignancies. Type 2 diabetes is characterised by increased oxidative DNA damage, telomere attrition, and an increased risk of colonic malignancy. We hypothesised that the colonic mucosa in Type 2 diabetes would be characterised by increased DNA damage and telomere shortening.

METHODS

We examined telomere length (by flow fluorescent in situ hybridization) and oxidative DNA damage (flow cytometry of 8 - oxoguanosine) in the colonic mucosal cells of subjects with type 2 diabetes (n = 10; mean age 62.2 years, mean HbA1c 6.9%) and 22 matched control subjects. No colonic pathology was apparent in these subjects at routine gastrointestinal investigations.

RESULTS

Mean colonic epithelial telomere length in the diabetes group was not significantly different from controls (10.6 [3.6] vs. 12.1 [3.4] Molecular Equivalent of Soluble Fluorochrome Units [MESF]; P = 0.5). Levels of oxidative DNA damage were similar in both T2DM and control groups (2.6 [0.6] vs. 2.5 [0.6] Mean Fluorescent Intensity [MFI]; P = 0.7). There was no significant relationship between oxidative DNA damage and telomere length in either group (both p > 0.1).

CONCLUSION

Colonic epithelium in Type 2 diabetes does not differ significantly from control colonic epithelium in oxidative DNA damage or telomere length. There is no evidence in this study for increased oxidative DNA damage or significant telomere attrition in colonic mucosa as a carcinogenic mechanism.

Vascular system: role of nitric oxide in cardiovascular diseases

In contrast with the short research history of the enzymatic synthesis of nitric oxide (NO), the introduction of nitrate-containing compounds for medicinal purposes marked its 150th anniversary in 1997. Glyceryl trinitrate (nitroglycerin) is the first compound of this category. On October 12, 1998, the Nobel Assembly awarded the Nobel Prize in Medicine or Physiology to scientists Robert Furchgott, Louis Ignarro, and Ferid Murad for their discoveries concerning NO as a signaling molecule in the cardiovascular system. NO-mediated signaling is a recognized component in various physiologic processes (eg, smooth muscle relaxation, inhibition of platelet and leukocyte aggregation, attenuation of vascular smooth muscle cell proliferation, neurotransmission, and immune defense), to name only a few. NO has also been implicated in the pathology of many inflammatory diseases, including arthritis, myocarditis, colitis, and nephritis and a large number of pathologic conditions such as amyotrophic lateral sclerosis, cancer, diabetes, and neurodegenerative diseases. Some of these processes (eg, smooth muscle relaxation, platelet aggregation, and neurotransmission) require only a brief production of NO at low nanomolar concentrations and are dependent on the recruitment of cyclic guanosine monophosphate (cGMP)-dependent signaling. Other processes are associated with direct interaction of NO or reactive nitrogen species derived from it with target proteins and requires a more sustained production of NO at higher concentrations but do not involve the cGMP pathway.

Effects of antihypertensive drugs on alcohol-induced functional responses of cultured human endothelial cells

Alcohol-induced endothelial changes might contribute to an increase in blood pressure in regular alcohol consumers. Some antihypertensive drugs affect oxidative stress and endothelial function and might counteract the effects of alcohol at the cellular level. The aim of this study was to investigate in vitro the effects of three different types of antihypertensive agents on alcohol-induced endothelial responses and oxidative stress. Cultured human endothelial cells were exposed to increasing concentrations (1, 10, 60 micromol/L) of zofenoprilat, carvedilol, and lacidipine in the absence and in the presence of ethanol (140 mmol/L). Concentrations of endothelin (ET) and nitric oxide (NO) were measured in the culture media as markers of endothelial function, and malondialdehyde (MDA) and intracellular glutathione (GSHi) were measured as markers of oxidative stress. Exposure to alcohol increased the levels of ET, NO, and MDA, and decreased GSHi. Carvedilol and zofenoprilat were more effective than lacidipine in counteracting the effects of alcohol on ET production. Alcohol-induced NO production was enhanced by carvedilol, whereas zofenoprilat and lacidipine did not have a significant effect. The alcohol-induced increase in MDA concentrations was blunted by all three drugs, but only carvedilol restored a normal response. All three drugs increased GSHi levels, with the effect being greater for carvedilol and lacidipine than zofenoprilat. Carvedilol is more effective than zofenoprilat and lacidipine in counteracting alcohol-induced endothelial responses in vitro and in decreasing oxidative stress. These effects might be particularly beneficial in patients with alcohol-related hypertension.

Effects of losartan and enalapril on high-sensitivity C-reactive protein and total antioxidant in renal transplant recipients with Renin-Angiotensin system polymorphisms

BACKGROUND

As renin-angiotensin system (RAS) activity may affect the severity of oxidative stress and inflammatory markers, we assessed the effects of enalapril (E) and/or losartan (L) on these markers in renal transplant recipients with RAS polymorphisms.

PATIENTS AND METHODS

After determination by PCR of RAS genotypes, consisting of the angiotensin-converting enzymes (ACE I/D), angiotensinogens (AGT M235T) and angiotensin II type 1 receptors (ATR1 A1166C), 76 recipients were recruited randomly and assigned 4 groups. The first (n = 17) and second (n = 24) groups were treated with E (E(+): 10 mg/d) and L (L(+): 50 mg/d) alone, respectively. The third positive control group (n = 17) received E + L (E(+)L(+): 10 mg/d + 50 mg/d) and the fourth negative control group (n = 18) received no medication (E(-):L(-)). High-sensitivity C-reactive protein (hs-CRP) and total antioxidant (TA) inflammatory and antioxidative markers were measured after 2 months. After a 2-week washout period, the E(+) group was changed to L(+) and vice versa in a crossover design. They were followed for another 8 weeks before retesting hs-CRP and TA. A value of P < or = .05 was considered significant.

RESULTS

After 2 and 4 months of treatment with the drug regimen, hs-CRP and TA levels were significantly decreased and consequently increased among the E(+)L(+), L(+) and E(+) groups (P < .05). On analyzing the relationship between RAS polymorphisms and baseline hs-CRP or TA levels, CC genotype of ATR1 showed lower hs-CRP levels (P = .04). However, none of the RAS polymorphisms predicted the antioxidant and anti-inflammatory response rates to the drugs (P > .05).

CONCLUSION

Although hs-CRP was lower in the CC genotype patients of ATR1 polymorphisms E and/or L reduced hs-CRP and increased TA regardless of the RAS genotype.

Human neutrophil peptides upregulate expression of COX-2 and endothelin-1 by inducing oxidative stress

Polymorphonuclear leukocytes (PMNs) play an important role during inflammation in cardiovascular diseases. Human neutrophil peptides (HNPs) are released from PMN granules upon activation and are conventionally involved in microbial killing. Recent studies suggested that HNPs may be involved in the pathogenesis of vascular abnormality by modulating inflammatory responses and vascular tone. Since HNPs directly interact with endothelium upon release from PMNs in the circulation, we tested the hypothesis that the stimulation with HNPs of endothelial cells modulates the expression of vasoactive by-products through altering cyclooxygenase (COX) activity. When human umbilical vein endothelial cells were stimulated with purified HNPs, we observed a time- and dose-dependent increase in the expression of COX-2, whereas COX-1 levels remained unchanged. Despite an increased expression of COX-2 at the protein level, HNPs did not significantly enhance the COX-2 activity, thus the production of the prostaglandin PGI2. HNPs significantly induced the release of endothelin-1 (ET-1) as well as the formation of nitrotyrosine. The HNP-induced COX-2 and ET-1 production was attenuated by the treatment with the oxygen free radical scavenger N-acetyl-L-cysteine and the inhibitors of p38 MAPK and NF-kappaB, respectively. The angiontensin II pathway did not seem to be involved in the HNP-induced upregulation of COX-2 and ET-1 since the use of the angiotensin-converting enzyme inhibitor enalapril had no effect in this context. In conclusion, HNP may play an important role in the pathogenesis of inflammatory cardiovascular diseases by activating endothelial cells to produce vasoactive by-products as a result of oxidative stress.

Protective effects of ACE inhibitors on vascular endothelial dysfunction induced by exogenous advanced oxidation protein products in rats

To explore detrimental effects of advanced oxidation protein products-bovine serum albumin (BSA) on endothelial function and compare the favorable effects of angiotensin-converting enzyme (ACE) inhibitors: captopril and enalapril. Male Sprague-Dawley rats were randomly divided into groups: control, advanced oxidation protein products-BSA, captopril (10, 20 mg/kg/day), enalapril (15 mg/kg/day), and N(G)-nitro-l-arginine methyl ester (l-NAME, 300 mg/kg/day) plus captopril (20 mg/kg/day) groups. All animals were given advanced oxidation protein products-BSA (100 mg/kg/day, i.v.) except for control group (iv. equal volume of PBS). Rats in other groups were received different drugs intragastrically after advanced oxidation protein products-BSA administration. Endothelium-dependent relaxation of thoracic aorta was assayed. Content of nitrite/nitrate (NO), malondialdehyde (MDA), activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and of ACE in Sera, as well as renal function index including blood urea nitrogen and creatinine were measured. After 30 days, the endothelium-dependent relaxation of blood vessels in received advanced oxidation protein products-BSA rats was significantly impaired compared with control rats. The impairment was accompanied by decreases of serum NO, activity of GSH-Px and SOD. Administration of captopril and enalapril not only decreased damage of endothelium-dependent relaxation, but also reverse the changes of MDA levels, NO content and activity of SOD. The protective effect of captopril was abolished by L-NAME. Blood urea nitrogen and creatinine had no significant differences between various groups. ACE activities were decreased in high captopril and enalapril groups, but did not significantly change in other groups. The results suggested that captopril and enalapril have similar effects on endothelial dysfunction induced by advanced oxidation protein products-BSA, which indicated that protective effects of captopril are not related to sulfhydryl group.

Prevention of DNA damage in renal transplantation by losartan and enalapril: the role of renin-angiotensin system polymorphisms

BACKGROUND

In this study the effect of losartan and enalapril on the reduction of DNA damage was evaluated in regard to renin-angiotensin system (RAS) polymorphisms.

METHODS

After determination of genotypes of RAS polymorphism by PCR, 64 renal transplant recipients were randomly allocated to one of four groups: the first and second groups were treated with E (E+: 10 mg/day) and L (L+: 50 mg/day) alone, respectively. The third group received E+L (E+L+: 10 + 50 mg/day), and the forth group received no medication (E-L-). The subjects were followed for 8 weeks. After a 2-week washout period, the E group changed to L and vice versa as a cross-over design. They were followed for another 8 weeks. Before and after treatment, we checked 8-OHdG and malondialdehyde (MDA) as biomarkers of DNA damage and lipid peroxidation, respectively.

RESULTS

8-OHdG levels were significantly decreased after treatment in the E+L+ and L+ groups (P < 0.001, P = 0.001, respectively). Only the TT genotype of AGT had the most antioxidative role regarding the treatment (P = 0.01). We found a remarkable correlation between MDA and DNA damage levels before and after intervention (r = 0.48, P < 0.001; r = 0.35, P = 0.006).

CONCLUSION

The protective effects of L+ and E+L+ on DNA breaks are surprising regarding the RAS polymorphisms.

Angiotensin-converting enzyme inhibitor captopril prevents oleic acid-induced severe acute lung injury in rats

Lack of specific and efficient therapy leads to the high mortality rate of acute lung injury (ALI) and acute respiratory distress (ARDS). Recent evidence implies that angiotensin-converting enzyme (ACE) plays an important role in the pathogenesis of ALI. Pharmaceutical inhibitors of ACE have been used clinically for hypertension but not for ALI/ARDS yet. The objective was to study the effects of ACE inhibition with captopril on severe lung injury induced by oleic acid (OA) in rats. Oleic acid was intravenously injected into Sprague Dawley rats, followed by i.p. administration of captopril or saline control. Lung injury, endothelium damage and related molecules, and disturbance of coagulation were examined in comparison between the treated and the nontreated groups. An OA-induced ALI was featured with thickening of the alveolar septa, alveolar hemorrhage, and infiltration of inflammatory cells. Comparing with the nontreated OA group, the administration of captopril prevented the rats from OA-induced severe lungs injury, with a significantly lower lung injury score, less albumin content and infiltrated cells in the alveoli, decreased wet/dry weight ratio of the lung tissues, and improved lung function (PaO2 per fraction of inspired oxygen). Captopril also dramatically reduced the expression of intercellular adhesion molecule-1 in the lung tissue and in the circulating endothelial cells in the blood, indicating a protective effect on endothelial cells activation/damage. Moreover, captopril treatment led to a blockage of nuclear factor kappaB activation in lung tissues and to the recovery of the fibrinolytic disturbance. Thus, our data suggest that the inhibition of ACE with its clinically used inhibitor offers protective effects on ALI/ARDS, implying the potential for therapeutic option.